Compressor



March 18 1958 A. E. SCHMiDLlN ETAL 2,

- COMPRESSOR Filed March 1, 1954 FIRST STAGE spam/b $734 CF w/zw 5 224as F0 UR TH 67?; c5

INVENTORS A/Jerlvsl78o1ngiofi'l; Warren E. Herr ATTORNEY United StatesPatent C) COMPRESSOR Albertus E. Schmidlin, Caldwell, and Warren E.Herr,

Hasbrouck Heights, N. 3., assignors to Specialties DeveloprnentCorporation, Belleville, N. 1., a corporation of New Jersey ApplicationMarch 1, 1954, Serial No. 413,276

5 Claims. (Cl. 230-184) The present invention relates to compressors,and, more particularly, to an air compressor of the multistage typewhich is an improvement over the four-stage radial compressor disclosedin United States Patent No. 2,562,954.

While compressors of the type described in the aforementioned patent canbe operated at high speeds to supply compressed air or other gases atpressures of 3000 pounds per square inch and a satisfactory rate offlow, it has been found that the compressors vibrate considerably andthat the keystone member and follower means are subjected to excessivewear.

Accordingly, an object of the present invention is to provide a radialmulti-stage compressor wherein vibrations are reduced to a minimum.

Another object is to provide such a compressor wherein the wear life ofthe cam and follower means is prolonged.

Another object is to reduce the size and mass of such a compressorwithout sacrifice of flow rate or output pressure.

A further object is to simplify the design of such compressors tothereby reduce the cost thereof and facilitate manufacture and assembly.

Other and further objects of the invention will be obvious upon anunderstanding of the illustrative embodiment about to be described, orwill be indicated in the appended claims, and various advantages notreferred to herein will occur to one skilled in the art upon employ mentof the invention in practice.

In accordance with the invention, the foregoing objects are accomplishedby embodying improvements in such compressors which comprise arrangingthe cylinders so that two are in vertical alignment and two are inhorizontal alignment, preferably with the longitudinal axes of thevertical cylinders and one of the horizontal cylinders intersecting atthe axis about which the shaft rotates (the other horizontal cylinderbeing ofiset with respect to the shaft axis) and with the first stagecylinder opposite the fourth stage cylinder and the second stagecylinder opposite the third stage cylinder; providing a cam having twocam surfaces at the sides which are parallel to each other and a thirdsurface at the bottom which is perpendicular to the parallel surfaceswith the fourth stage piston cam follower means engaging the bottomsurface and the second and third stage piston cam follower meansengaging the side surfaces; and providing cam follower means which arerigid with respect to the pistons carrying the same, and whichpreferably are integrally formed or secured therewith.

A preferred embodiment of the invention has been chosen for purposes ofillustration and description, and is shown in the accompanying drawing,forming a part of the specification, wherein the single figure is afront elevational view, partly in longitudinal section, of a radialmulti-stage compressor illustrating the essential elements of thepresent invention and their arrangement.

Referring to the drawing, there is shown a radial 2,827,227 PatentedMar. 18, 1958 multi-stage compressor generally comprising a casing orhousing 10 having a first stage cylinder 11 at the top, sec ond andthird stage cylinders 12 and 13 at the sides and a fourth stage cylinder14 at the bottom; a drive shaft 15 (shown in broken lines) journalledfor rotation and supported by the casing, for example, as shown in theaforementioned patent, including an eccentric, such as a crank 16 withinthe casing; pistons 17, 13, 19 and 20 for the first, second, third andfourth stage cylinders, respectively; and a cam 21 carried by the crankwhich is operatively associated with the pistons for effecting reciprocation thereof.

As shown herein the first and fourth stage cylinders are in verticalalignment and the second and third stage cylinders are substantially inhorizontal alignment but with axis of the third stage cylinder slightlyabove the axis of the second stage cylinder. In this manner, torqueforces acting on the cam about the axis of the shaft are minimized, andthe sum of the components of the vertical forces is substantially equalto that of the horizontal forces.

The details of the inlets and outlets of the cylinders and the valvingassociated therewith, and the outer ends of the pistons are not shownbecause the present invention is not concerned therewith. A suitablearrangement of such elements is illustrated in the aforementioned patcut. The outlets of the first, second and third stage cylinders arerespectively connected to the inlets of the second, third and fourthstage cylinders. The bore of the cylinders decreases in the order inwhich the cylinders are named numerically.

The first stage piston 17 carries a horizontal pin or rod 22 at thelower end thereof which extends through a horizontal bearing aperture 23at the upper end of the cam 21 to slidably connect the cam and piston,whereby circular movement of the cam under the influence of the crankimparts reciprocating movement to the piston 17.

The cam 21, as shown, has a pair of vertical, parallel side surfaces 24and 25, and a horizontal bottom surface 26 perpendicular to the sidesurfaces. The second, third and fourth stage pistons have cam followermeans 27, 28 and 29, respectively, for engaging the cam surfaces in theorder named. As shown herein, the cam follower means are in the form ofrigid heads integrally formed or secured at the inner ends of theirrespective pistons and having fiat faces parallel to the cam surfacethey engage. Also, as illustrated in the aforementioned patent, thepistons 18, 19 and 20 are so arranged that they do not displace all theair compressed in their cylinders, whereby the compressed air remainingtherein is effective to cause the pistons to be urged towards the camblock 21 after their compression stroke to maintain their followers inengagement with the cam surfaces.

With this arrangement, the cam followers of the horizontal second andthird stage pistons serve as a slide or guide to maintain the cam invertical alignment and all the forces applied between the cam and thesefollowers are parallel to the pin 22, whereby no wedging forces areapplied between the pin and the cam so that the wear life of the pin andthe bearing is greatly prolonged. The only forces applied between theseelements are sliding friction between the pin and the bearing, and thevertical thrust of the cam bearing on the pin in moving the first stagepiston up and down. Also, since tilting movement of the cam is preventedand the cam followers are rigid, the followers are constantly in slidingengagement with the cam surfaces without freedom of movement other thansuch sliding movement, whereby noise and vibration are practicallyeliminated within the compressor casing.

By arranging the stages as indicated herein, the forces acting on thecam and the forces transmitted by the cam are almost in perfect dynamicbalance. This also is in- 3 struniental in reducing vibr'ati'on'and wearof contacting parts. In viewof such vibration and wearreduction, the

compressor may be smaller in mass and size than prior compressors ofthis general type having the same output flow and pressure rating. V

From the foregoing description, it will be seen that the presentinvention provides a highly improved radial multi-stage compressor'whichhas a high output weight rating, at a given pressure, and which iseconomical to manufacture'and durable in construction.

As various changes may be made 'in the form, construction andarrangement of the parts herein, without departing from the spirit andscope'of the invention and without sacrificing any of its advantages, itis to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

Weclaim': V p 1; In a radial multi-stage compressor, the combination ofa driveshaft including an eccentric, first, second, third and fourthstage cylinders, said cylinders being radially disposed with respect tosaid shaft and spaced circumferentially with respect to each other withtwo of said cylinders in vertical alignment and two'of said cylinderssubstantially in horizontal alignment, acarn mem ber carried by saideccentric for movement in a circular path, said cam member having threelinear surfaces, 21

piston for said first stage cylinder, means for slidably connecting'said cam member to said piston whereby said cam member impartsreciprocating motion thereto, and

' pistons for said second, third and fourth stage cylinders havingfollower means each adapted to be slidably engaged; by a surface of saidcam-member to effect reciprocation of the last mentioned pistons, thelongitudinal axes'of said vertical" cylinders'and one of said horizontalcylinders intersecting at the axis about which said shaft rotates, andthe axis of the other of said horizontal cylinders extending slightlyabove the shaft axis.

2. A compressor according, to claim 1, wherein two of said cam surfacesare parallel to each other and the, other of said cam surfaces:isperpendicular to said two parallel surfaces.

3. A compressor according-to claim 2, whereinzsaid 7 I References Citedin thefile of this patent UNITED STATES PATENTS 2,427,253 Browne Sept.9', 1'94? 2,450,468 Cornelius Oct. 5, 1948 2,562,954 Schmidlin Aug. 7,1951 V FOREIGN PATENTS 902,097 France Nov. 27; 1944 France Oct. 15, 1952

